Artificial tooth



April 19, 1960 M, MARDER 2,932,893

ARTIFICIAL TOOTH Filed June 7, 1955 FIG.2

INVENTOR.

M ax M avd mr Q3 WQ QSQULM limited States Patent O "ice ARTIFICIAL TOOTHMax Marder, Paris, France Application June 7, 1955, Serial No. 513,695Claims priority, application France November 10, 1951 Claims. (Cl.32-10) The present invention relates to artificial teeth to be used byhuman beings.

More particularly, the present invention relates to faeings ofartificial teeth.

The present application is a continuation-in-part of application SerialNo. 301,744 filed July 30, 1952, and now abandoned and entitledArtificial Tooth, of application Serial No. 301,745, filed July 30,1952, andnow abandoned, and entitled Artificial Teeth, and ofapplication Serial No. 272,920, filed February 23, 1952, and nowabandoned and entitled Artificial Tooth.

In the art of artificial teeth, the most desirable results are producedwhen an artificial tooth, or at least the visible facing thereof,resembles a natural tooth so closely as to be indistinguishabletherefrom. Thus far, this result has not been produced becauseconventional facings of artificial teeth are made of translucentmaterials which to the naked eye appear darker than natural teethbecause the facings appear to have the color of the cement locatedbehind the facing.

One of the objects of the present invention is to provide an artificialtooth facing which, when in use, resembles a natural tooth so closely asto be indistinguishable therefrom.

Another object of the present invention is to provide an artificialtooth facing with a light reflecting and diffracting means capable ofgiving the facing a natural appearance. .A further object of the presentinvention is to provide a light reflecting and diffracting means of theabove type which at the same time serves to improve the strength of theartificial tooth and the security with which it is mounted.

With the above objects in view the present invention mainly consists ofan artificial tooth which includes a translucent facing having a frontsurface adapted to be exposed when in use and a rear surface adapted tobe joined to a support for the facing. A foraminous diffracting andreflecting sheet means, preferably made up of silver coated filaments ofcircular cross section, engages the facing and is located adjacent therear surface of the facing for reflecting and diifracting light passingthrough the front surface thereof into the facing back throughth'e'jfacing and out through the front surface thereof and for giving tothe facing a coloring closely approximating that of aInatural tooth. v

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects andradvantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a sectional view taken in a horizontal plane through avertically positioned facing constructed in accordance with the presentinvention;

2,932,893 Patented Apr. 19, 1960 Fig. 2 is a perspective view of anotherembodiment of a facing of the present invention as seen when lookingtoward the rear surface thereof;

Fig. 3 is a side elevational view of another embodi ment of a facingconstructed in accordance with the present invention;

Fig. 4 is a sectional view taken along line 4-4 of Fig. 3 in thedirection of the arrows;

Fig. 5 is a partly sectional view taken along line 5-5 of Fig. 3 in thedirection of the arrows; and

Fig. 6 is a sectional view on an enlarged scale corresponding to Fig. 4and illustrating the principle on which the invention is based.

The present invention is limited to facings for artificial teeth, andthese facings can be supported in a conventional manner. The facings aremade of a translucent material so that light can pass therethrough. Thusthe facing may be made of a translucent ceramic material such asporcelain or of a translucent synthetic resin such as an acrylic resin.A natural tooth does not have a uniform color, and therefore thematerial of the facing of the present invention is not relied upon togive the facing the coloring which it appears to have when used.Instead, a foraminous sheet means, such as a gauze sheet, is inengagement with the facing of the invention, is located adjacent therear face thereof, and has an extremely white color so that the coloringof the facing of the invention is provided by light reflected withdiffraction from this foraminous sheet means back through the facingtoward the observer. In this way, as will be apparent from thedescription which follows, the facing of the invention has a uniformcolor which very closely approximates the coloring of a natural tooth.The reflected rays cross each other and mask the darker elements behindthe facing. It is possible to manufacture the facings of the inventionby molding them in suitably shaped molds.

Referring to Fig. l, the facing 10 shown is made of any of the abovementioned translucent materials and has a foraminous sheet means 11embedded therein. It will be noted that the sheet means 11 is locatedadjacent the rear face 12 of the facing 10 and has an omega crosssection. In the remainder of this specification it is to be understoodthat an omega cross section signifies a shape corresponding to that ofthe Greek capital letter omega. This sheet means 11 is preferably in theform of a metallic gauze consisting of a mesh of extremely finefilaments. As was pointed out above the best results are obtained by aforaminous sheet means which is as whit-e as possible. Thus, the metalof the gauze sheet cannot be platinum, for example, because such a metalis gray rather than white. It is preferred to make the gauze sheet 11 ofwire filaments which are coated with silver. This latter constructionhas been found in practice to give the best possible results. The facing10 shown in Fig. 1 may be supported on a bridgework or the like in anyconventional manner.

Fig. 2 shows a facing 13 made of any of the above materials and formedin its rear face with an elongated groove 14 which gives the rear facean omega-shaped cross section. This groove 14 is adapted to receive apost of a support in a known way for mounting the facing. Against therear surface 15 of the facing 13 is located the foraminous sheet means16 which is preferably in the form of a metallic gauze sheet made up ofa fine mesh work of silver coated filaments. It will be noted that thesheet means 16 covers the surface of the groove 14 in addition to asubstantial portion of rear face 15 beyond groove 14. The sheet means 16may be joined to the facing 13 as by being partially embedded thereinduring the molding thereof, or any adhesive may be used for thispurpose. As was pointed out above and as will be further discussed belowthe foraminous sheet means of the invention gives the facing a verynatural coloring. in the embodiment of Fig. l, the sheet means 11performs the additional function of reinforcing the facing, and in theembodiment of Fig. 2 the sheet means also reinforces the facing andadditionally provides it with a rough rear surface which increases thesecurity of the mounting of the facing. That is, when an adhesive cooperates with the irregular rear surface of the facing of Fig. 2 tofasten this facing to a support, the bond is much stronger than would bethe case if rear surface 15 were smooth. The rough rear surface isprovided by pressing the sheet means against the rear surface of thefacing while the latter is still plastic, and the material of the facingfiows throughthe spaces between the filaments to provide the facing withrearwardly extending projections as shown in Fig. 6.

In the embodiment shown in Figs. 3-5, the facing 17 has a rear surfacemade up of a rear surface portion 18 and a rear surface portion 19-,these latter rear surface portions being substantially at right anglesto each other. Facing 17 is made of a-ny 'o'f the above mentionedtranslucent materials. Only the rear surface portion 19 is formed withan elongated groove 20 to give rear surface portion 19 an omega-shapedcross section. Fig. 3 shows in dot-dash lines a conventional support 21carrying the facing 17 and having a post of omega cross section matingwith and fitting into the groove 20. A foraminous sheet means isembedded within the facing 17 closely adjacent to the rear face 13, 19thereof, as shown in Figs. 3-5. This foraminous sheet means ispreferably a metallic gauze as described above and includes a planeportion 22 located adjacent the rear surface portion 18 and a portion 23of omega cross section located adjacent rear surface 19 and conformingclosely to the groove 20, as shown in Fig. 4.

As is evident from the enlarged sectional view shown in Fig. 6, thegauze sheet which forms the forarninous sheet means of the invention'iscomposed of filaments 24 which are coated with silver and which are ofcircular cross section. This gauze sheet is pressed into the rearsurface of the casing facing while the material thereof is still plasticto provide the facing with realwardly extending projections surroundedby the filaments of the gauze sheet.

The principle of the invention can be understood from Fig. 6 withrespect to the parallel light rays A and B of monochromatic light whichmove in the direction of the arrows toward the facing of the invention.As is evident from Fig.6 parts of these light rays are reflected fromthe front surface of the facing as light rays A and B The remainder ofthese light rays enter into the facing and are refracted to form thelight rays A and B respectively. The light ray B strikes one of thefilaments and then moves back through the facing toward the frontsurface thereof as the light ray B this latter light ray being refractedagain at the front surface of the facing and emerging as light ray B Onthe other hand, the light ray A encounters another filament 24 and thenmoves back toward the front surface of the facing as light ray A thislatter light tr'ay being refracted at the front surface of thefacing andemerging as light ray A It will be noted that thelight rays A 'and A-cross'overthe light rays B and B When it is considered that an infinitenumber of light rays move in the manner indicated for the light "rays Aand B and that these lightrays cro's's each other in the material ofth'efacing an infinite number of tiiries, it *v'vill'b'e understood thatthese light rays "serve to mask any dark colors of the elements whichcarry the facing "so that these 'dark colors cannot give the facing'a'n'unn'atirrhl appearance.

It should also be noted that the cross sectional area of the projectionsof the facing which extend re'arwardly through the gauze sheet issubstantially smaller than the cross sectional area of'the filamentswhich makeup this sheet. This is a further feature which contributes tothe desired results.

It has been found in actual practice that the above described structureprovides an artificial tooth facing which cannot be distinguished from anatural tooth, when in use. This result is obtained by the translucencyof the facing and by the extreme whiteness of the silver coatedfilaments of the forarninous sheet means.

It will be understood that each ofthe elements described above, or twoor more together, may also find a useful application in other types ofartificial teeth differing from the types described above.

While the invention has been illustrated and described as embodied infacings for artificial teeth, it is not intended to be limited to thedetails shown, since various modifications and structural changes may bemade without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully re've'al the'gistof the present invention that others can by applying current knowledgereadily adapt it'for various 7 applications without omitting featuresthat, from the.

standpoint of prior art, fairly constitute essential characteristics ofthegeneric or specific aspects of this invention and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. For use in an artificial tooth, in combination, a {racing itavrng afront surface adapted robe exposed when in use and a rear surfaceadapted to be joined to a sup port for "the facing, said facing beingmade of a translu'ce'ht 'rn'olded material through which light can pass;'and a game sheet of a light color engaging said'facing and locatedadjacent the rear surface thereof for diffracting and reflecting lightpassing through said front surface of "said fa'cin'g into the latterback through said facing and out through said front surface thereof andfor giving to the facing a coloring closely 'aproxirna'tingthat of anatural tooth. j

"2. For use in an artificial tooth, in combination, a facinghaving afront surface adapted to'be exposed when in use and a rear surfaceadapted to be joined to a support 'f'orfthe facing, said facing beingmade of a translu'ce'nt molded material through which light can pass;and a gauze sheet of a light color engaging said facing andllo'c'atedadajacent'the rear surface thereof for diffracting and reflecting lightpassing through said front surface of sate facing into the latter backthrough said facing and out through said fro'ntsurface thereof andforgiving to the facing a coloring closely approximating that of anatural tooth, sa'id rear surface of said facing having a plurality ofprojections which extend rearwardly through said gauze sheet. 7 3. --Foruse in an artificial tooth, 'in combination, a facing having a "frontsurface adapted to be exposed when in use and a rear surface adapted tobe joined to 'a support "fo'r't-he facing, said facing being made of atranslucerit "molded material through which light can pass; and a gauzesheet or alight color "composed of individual "iet'all-ic filaments "ofcircularj'cross section, engaging "s' dieting and loc'a tedadjacenttherefar'surfac'e thereof fi st diffracting anti Iiefl'e'c'tin'g lightpassing through said front surface of said facing into th eflatter backthrough said :facing g'a'n'd out through said front surface thereofanujrorgivingtb -the facing a coloring closely approxie I'Iiiaftinfgthat 'bfh'.rti1'tilfal"f0'dth. I 1

4. For use :in an "artificial tooth, incombina'tion, a

facing-having affront s u'rface'fadapted'to be exposed when in e and fafrat surface adapted "to be joined to 'a su port forthe facing, saidfacing being made of a translucent molded material through 'which lightcan pass; and a gauze sheet of a pure white coro'r composed ofindividual 'silver coated 'filairfeiits of circular cross section,

engaging said facing and located adjacent the rear surinto the rearsurface of the facing, while the material face thereof for difi ractingand reflecting light passing thereof is still plastic, until the rearsurface is provided through said front surface of said facing into thelatter with projections extending through the gauze sheet. back throughsaid facing and out through sa1d front sur- References Cited in the fileof this Patent face thereof and for giving to the facing a colormgclosely 5' approximating that of a natural tooth. UNITED STATES PATENTS5. A. process for manufacturing a facing for an arti- 1,296,009 RichardsMar. 4, 1919 ficial tooth, comprising the steps of molding a facing2,147,403 Freedman Feb. 14, 1939 from a translucent material; andpressing a gauze sheet 2,572,377 OMorrow Oct. 23, 1951

